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Title: 30 years of progress toward increased biomass yield of switchgrass and big bluestem

item Casler, Michael
item Vogel, Kenneth
item LEE, D. - University Of Illinois
item Mitchell, Robert - Rob
item Adler, Paul
item SULC, R. - The Ohio State University
item JOHNSON, KEITH - Purdue University
item KALLENBACH, ROBERT - University Of Missouri
item BOE, ARVID - South Dakota State University
item MOORE, KENNETH - Iowa State University

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/31/2018
Publication Date: 5/3/2018
Publication URL:
Citation: Casler, M.D., Vogel, K.P., Lee, D.K., Mitchell, R., Adler, P.R., Sulc, R., Johnson, K., Kallenbach, R., Boe, A., Moore, K. 2018. 30 years of progress toward increased biomass yield of switchgrass and big bluestem. Crop Science. 58:1242–1254.

Interpretive Summary: Switchgrass and big bluestem are two grasses being developed as biomass crops for conversion to bioenergy. A fundamental requirement for this industry is to create new varieties with greater biomass yield potential than is available from existing forage varieties. New candidate varieties of these two grasses were evaluated in field trials for five years at 13 locations, ranging from Nebraska to Pennsylvania and from northern Minnesota, Wisconsin, and Michigan to central Missouri. Significant progress was made by two USDA-ARS breeding programs (Lincoln, NE and Madison, WI) toward improving biomass yield of both grasses, with realized gains as high as 40% greater than existing forage varieties. These results will be of great value in documenting the performance of several new varieties to be released to the public in the next few years, as well as providing other researchers with a model for testing candidate varieties of these and other grasses.

Technical Abstract: Breeding to improved biomass production of switchgrass and big bluestem for conversion to bioenergy began in 1992. The purpose of this study was (1) to develop a platform for uniform regional testing of cultivars and experimental populations for these species and (2) to estimate the gains made by breeding during 1992 to 2012. A total of 25 switchgrass populations and 16 big bluestem populations were planted in uniform regional trials at 13 locations in 2012 and 2014. The reference region was USDA hardiness zones 3 through 6 in the humid temperate region of the USA (from the eastern Great Plains to Pennsylvania). Significant progress toward increased biomass yield was made within upland-ecotype populations, lowland-ecotype populations, and hybrid-derived populations. Four mechanisms of increasing biomass yield were documented: (1) increased biomass yield per se, (2) later flowering to extend the growing season, (3) combined later flowering from the lowland ecotype with survivorship of the upland ecotype in hybrid-derived populations, and (4) increased survivorship of late-flowering lowland populations in hardiness zones that represent an expansion of their adaption zone. The uniform testing program was highly successful at documenting increases in biomass yield, identifying the mechanisms for increased yield, and determining adaptation characteristics and limitations of improved populations.